How can I decrease size of rootfs and kernel uImage?

[stack_shailesh]

I have doubts, please give solution. I am using stm32mp135f series processor.

1. How should I remove all components of stm32mp135f-dk-a7-examples from rootfs, I want my device to boot fast and but for few seconds it waits for stm32mp135f-dk-a7-examples.dtb. I have doubts its components increasing rootfs size.

2. How can I decrease size of rootfs and kernel uImage.?

3. Can I use .tar file of rootfs in place of ext4 format for my hardware and use stm32cube programmer to upload all rootfs?